The largest workplace health study ever conducted is applying cutting-edge techniques to investigating an apparent cancer cluster—and highlighting the reasons why science doesn’t always protect us at work

“It’s green, it’s clean, it’s never seen — that’s nanotechnology!” That exuberant motto, used by an executive at a nanotech trade group, reflects the enthusiasm about nanotechnology, now used in everything from computer keyboards to toothpaste. But the motto is open for debate. For while nanotech does hold clean and green potential, it also poses possible serious risks to the environment and human health — risks that researchers have barely begun to probe, and regulators have barely begun to regulate.

Black lung disease used to be nearly as common as dirty fingernails among American coal miners. Now it’s back: After a 90 percent drop, the rate of the deadly illness has doubled in recent years. Federal scientists are trying to find out why.